Single transducer underwater structure high frequency target strength measurement device and method

Abstract

This invention belongs to the field of underwater acoustic measurement technology, specifically relating to a single-transducer underwater component high-frequency target intensity measurement device and method, including a transducer, an underwater component, a T / R switch, a signal transmitter, and a signal receiver. The signal transmitter generates a sinusoidal pulse signal and drives the transducer to emit an acoustic signal. The signal receiver converts the electrical signals at both ends of the transducer into digital signals and extracts and calculates specularly reflected sound waves and elastically scattered sound waves. This invention uses a single transducer, which serves as both a transmitter and a receiver, and achieves accurate measurement of the high-frequency target intensity of underwater components through specularly reflected and scattered sound wave separation technology. It completely compensates for the measurement errors introduced by the directional distribution of hydrophones and the arrangement of the transmitter-receiver-underwater component, and can significantly improve the measurement accuracy of the high-frequency target intensity of underwater components.

Description

Technical Field

[0001] This invention belongs to the field of underwater acoustic measurement technology, specifically relating to a device and method for measuring the high-frequency target intensity of a single transducer underwater component. Background Technology

[0002] Measuring the intensity of high-frequency targets on underwater components is fundamental to underwater imaging, torpedo detection, and underwater countermeasures, and plays a crucial role in the development of high-frequency underwater acoustic equipment. Currently, the main methods for measuring target intensity include near-field acoustic holography, comparison methods, transponder methods, and direct methods.

[0003] Among them, the acoustic holography method measures the sound pressure amplitude and phase on the near-field acoustic holographic surface of an underwater component, and then extrapolates the far-field scattered sound pressure using the Helmholtz integral formula to further obtain the target intensity of the underwater component. The measurement accuracy of this method is closely related to the grid division of the acoustic holographic surface. Typically, six measurement points are required within one wavelength. However, as the sound wave frequency increases, the wavelength becomes shorter, making it impossible to meet the number of measurement points. Therefore, this method is generally only applicable to acoustic scattering measurements within the frequency range of 10kHz. The comparison method obtains the target intensity of the underwater component by comparing the echo of the underwater component with the echo of a reference target. This method usually requires that the reference target and the underwater component have similar geometric characteristics, and its measurement accuracy depends entirely on the measurement uncertainty of the reference target. The transponder method is an improved version of the comparison method. It uses a transponder instead of a reference target in the comparison method. This method is mainly suitable for measuring the low-frequency target intensity of large underwater components in large water areas such as lakes and seas. The direct method measures the source level (SL), echo level (EL), and propagation loss (TL), and then uses the active sonar equations to obtain the target strength of underwater components. This method is a general method for measuring the target strength of underwater components, and the national standard GB / T 31014—2014 "Laboratory Method for Measuring the Intensity of Underwater Acoustic Targets" also adopts this method.

[0004] However, at sound wave frequencies above 100 kHz, the spatial distribution of sound scattering from underwater components is extremely uneven. In this case, the acoustic centers of the transmitter, receiver, and underwater component must be strictly collinear. For high-frequency target intensity measurements, hydrophones are typically used as receivers for both incident and scattered sound waves. At higher sound wave frequencies, the sensitivity of hydrophones differs significantly between the incident and scattered sound wave directions, reducing the accuracy of acoustic target intensity measurements. Furthermore, arranging the acoustic field of the transmitting transducer, hydrophone, and the underwater component under test is difficult, making it challenging to ensure that their acoustic centers are collinear. At high frequencies, the spatial distribution of target intensity in underwater materials varies greatly. When the three components are not collinear, the measurement reflects the intensity of a dual-base station target, and the results differ significantly from those of a single-base station target (usually referred to simply as target intensity). Summary of the Invention

[0005] This invention provides the following technical solution:

[0006] A high-frequency target intensity measurement device for underwater components with a single transducer includes a transducer, an underwater component, a T / R switch, a signal transmitter, and a signal receiver. The transducer generates sound waves in the water and receives echoes from the underwater component. The signal transmitter generates sinusoidal pulse signals and drives the transducer to emit sound signals. The signal receiver converts the electrical signals at both ends of the transducer into digital signals and extracts and calculates specular reflection sound waves and elastically scattered sound waves. The T / R switch controls the transmission and reception of the transducer.

[0007] Furthermore, the transducer and the underwater component remain at the same depth in the water.

[0008] Furthermore, the closing direction of the T / R switch is controlled by a pulse level.

[0009] Furthermore, the dimensions of the underwater component are much larger than the wavelength of the sound wave, satisfying... , Where λ is the wavelength of the sound wave, and L is the maximum length of the underwater component in the direction of the sound beam.

[0010] Furthermore, the pulse width of the sinusoidal pulse signal generated by the signal transmitter should be less than [a certain value]. The pulse repetition period is not less than , where c is the speed of sound in water.

[0011] A measurement method using the single-transducer underwater component high-frequency target intensity measuring device includes the following steps:

[0012] S1. A sinusoidal pulse signal is generated by the signal transmitter. After the rising edge of the synchronization signal level of the signal transmitter is detected by the T / R switch, the T / R switch is switched to the transmission state, and the transducer is controlled to generate a pulse sound signal in the water.

[0013] S2. When the synchronization signal level is a falling edge, the T / R switch switches to the receiving state, controls the transducer to receive the echo from the underwater structure, and the signal receiver converts the electrical signals at both ends of the transducer into digital signals.

[0014] S3. Adjust the position of the transducer according to the magnitude of the echo, so that its main beam is aligned with the underwater component, and at the same time, the signal receiver extracts the specular reflection wave and elastically scattered sound wave from the echo signal.

[0015] S4. Calculate the target strength of the underwater component as follows:

[0016]

[0017] in, Let ω be the angular frequency of the sound wave, and r be the distance between the transducer and the underwater structure. To reflect sound waves as a mirror, It is an elastically scattered sound wave.

[0018] Furthermore, the signal extraction method of the signal receiver has the following steps:

[0019] 1) Perform peak detection on the received signal and extract all peak points of the received signal. The i-th peak point is denoted as . , where t i Let i be the time of the i-th peak. Let be the signal amplitude at time i.

[0020] 2) Subtract the times of two adjacent peak points to obtain...

[0021] ;

[0022] 3) Obtain The maximum value, for all Compare with a threshold; if it exceeds the threshold, then a judgment is made. The effective peak value is denoted as . ;

[0023] 4) To If sorted, then... , N is the index of the last peak. The time of any two adjacent valid peaks is subtracted to obtain...

[0024]

[0025] and obtain maximum value Looking for the first one Then there is , .

[0026] 5) In to The signal within a time period is a specular reflection wave, in to The signal within the time frame is an elastically scattered wave.

[0027] In summary, compared with the prior art, the above-described technical solutions conceived by this invention can achieve the following beneficial effects:

[0028] This invention effectively overcomes the main limitations of existing underwater component target strength measurement technologies. Compared with traditional methods, this invention adopts a transducer design that integrates transmitting and receiving functions into a single transducer. This not only simplifies the measurement system structure but also significantly reduces the difficulty of underwater alignment. Effective measurement can be completed simply by ensuring that the main beam is aligned with the component under test. At the same time, this method extracts the specular reflection and elastic scattering sound waves of the underwater component, enabling direct acquisition of target strength even when the receiver sensitivity is unknown. This avoids the high-frequency measurement errors caused by receiver directivity in traditional direct methods. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the measuring device structure of the present invention;

[0030] Figure 2 This is a schematic diagram of the T / R switch of the present invention;

[0031] Figure 3 This is a schematic diagram of the signal extraction method of the present invention.

[0032] The markings in the image are as follows:

[0033] 1-Transducer; 2-Underwater component; 3-T / R switch; 4-Signal transmitter; 5-Signal receiver. Detailed Implementation

[0034] The specific embodiments of the present invention are described in detail below with reference to the accompanying drawings, so that those skilled in the art can more clearly understand how to practice the present invention. Although the present invention has been described in conjunction with its preferred embodiments, these embodiments are merely illustrative and not intended to limit the scope of the invention.

[0035] The target intensity mentioned in this invention is: the ratio of the sound intensity reflected back from the target at a distance of 1 m from the sound center of the target to the incident sound intensity, multiplied by 10 with the logarithm to the base 10; it is sometimes also called the single-base station target intensity. Sound scattering is a physical phenomenon, and target intensity is a quantitative measure of this phenomenon.

[0036] As attached Figure 1 As shown, a high-frequency target intensity measuring device for a single-transducer underwater component includes a transducer 1, an underwater component 2, a T / R switch 3, a signal transmitter 4, and a signal receiver 5. The transducer 1 generates sound waves in the water and receives echoes from the underwater component 2. The signal transmitter 4 generates sinusoidal pulse signals and drives the transducer 1 to emit sound signals. The signal receiver 5 converts the electrical signals at both ends of the transducer 1 into digital signals and realizes the extraction and calculation of specular reflection sound waves and elastic scattering sound waves. The T / R switch 3 controls the transmission and reception of the transducer 1.

[0037] Transducer 1 serves as both a transmitter and a receiver. Signal transmitter 4 and signal receiver 5 are both dry-end devices connected to transducer 1 via watertight wires. T / R switch 3 is also connected to transducer 1, signal transmitter 45, and signal receiver respectively.

[0038] Specifically, the transducer 1 and the underwater component 2 are kept at the same depth in the water, so that they are in each other's far field.

[0039] Specifically, the closing direction of the T / R switch 3 is controlled by a pulse level, as shown in the attached diagram. Figure 2 As shown, the closing direction of the T / R switch 3 is controlled by the pulse level to realize the transmission and reception of the signal of the transducer 1. The rising edge transmits tangentially and the falling edge receives tangentially.

[0040] Specifically, the size of the underwater component 2 is much larger than the wavelength of the sound wave, satisfying... , Where L is the wavelength of the sound wave, and L is the maximum length of underwater component 2 in the direction of the sound beam, i.e., applicable to... High-frequency target strength measurement of underwater components.

[0041] Specifically, the pulse width of the sinusoidal pulse signal generated by the signal transmitter 4 should be less than [a certain value]. The pulse repetition period is not less than , where c is the speed of sound in water.

[0042] A measurement method using the single-transducer underwater component high-frequency target intensity measuring device includes the following steps:

[0043] S1. A sinusoidal pulse signal is generated by the signal transmitter 4. After the rising edge of the synchronization signal level of the signal transmitter 4 is detected by the T / R switch 3, the T / R switch 3 is switched to the transmission state, and the transducer 1 is controlled to generate a pulse sound signal in the water.

[0044] S2. When the synchronization signal level is a falling edge, the T / R switch 3 switches to the receiving state, controls the transducer 1 to receive the echo from the underwater component 2, and the signal receiver 5 converts the electrical signals at both ends of the transducer 1 into digital signals.

[0045] S3. Adjust the position of transducer 1 according to the echo amplitude so that its main beam is aligned with the underwater component 2. At the same time, the signal receiver 5 extracts the specular reflection wave and elastically scattered sound wave from the echo signal. A typical signal of the signal receiver 5 is shown in the attached figure. Figure 3 As shown;

[0046] S4. Calculate the target strength of the underwater component as follows:

[0047]

[0048] in, Let be the angular frequency of the sound wave, and r be the distance between transducer 1 and underwater component 2. To reflect sound waves as a mirror, It is an elastically scattered sound wave.

[0049] Specifically, the signal extraction method of the signal receiver 5 has the following steps:

[0050] 1) Perform peak detection on the received signal and extract all peak points of the received signal. The i-th peak point is denoted as . , where t i Let i be the time of the i-th peak. Let be the signal amplitude at time i.

[0051] 2) Subtract the times of two adjacent peak points to obtain...

[0052] ;

[0053] 3) Obtain The maximum value, for all The comparison is performed against a threshold, which is related to the ratio of the sampling frequency to the signal frequency. A threshold is set when the ratio is greater than 10. ,when If it exceeds the threshold, then a decision is made. The effective peak value is denoted as . ;

[0054] 4) To If sorted, then... , N is the index of the last peak. The time of any two adjacent valid peaks is subtracted to obtain...

[0055]

[0056] and obtain maximum value Looking for the first one Then there is , .

[0057] 5) In to The signal within a time period is a specular reflection wave, in to The signal within the time frame is an elastically scattered wave.

[0058] This invention uses a single transducer 1 as both a transmitter and a receiver. The closing direction of the T / R switch 3 is controlled by the pulse level to realize the transmission and reception of signals from the transducer 1. The rising edge is tangentially transmitted, and the falling edge is tangentially received. By extracting the specular reflection wave and elastically scattered sound wave from the echo signal, the high-frequency target intensity of the underwater component 2 can be directly measured.

[0059] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications and substitutions based on the technical solutions and inventive concepts provided by the present invention should be covered within the scope of protection of the present invention.

Claims

1. A high-frequency target strength measuring device for a single transducer underwater component, characterized in that: It includes a transducer (1), an underwater component (2), a T / R switch (3), a signal transmitter (4), and a signal receiver (5); the transducer (1) generates sound waves in the water and receives echoes from the underwater component (2); the signal transmitter (4) generates sinusoidal pulse signals and drives the transducer (1) to emit sound signals; the signal receiver (5) converts the electrical signals at both ends of the transducer (1) into digital signals and realizes the extraction and calculation of specular reflection sound waves and elastic scattering sound waves; the T / R switch (3) controls the transmission and reception of the transducer (1).

2. The high-frequency target strength measuring device for a single transducer underwater component according to claim 1, characterized in that: The transducer (1) and the underwater component (2) are kept at the same depth in the water.

3. The high-frequency target strength measuring device for a single transducer underwater component according to claim 1, characterized in that: The closing direction of the T / R switch (3) is controlled by the pulse level.

4. The high-frequency target strength measuring device for a single transducer underwater component according to claim 1, characterized in that: The size of the underwater component (2) is much larger than the wavelength of the sound wave, satisfying the requirement that... , L is the wavelength of the sound wave, and L is the maximum length of the underwater component (2) in the direction of the sound beam.

5. The high-frequency target strength measuring device for a single transducer underwater component according to claim 4, characterized in that: The pulse width of the sinusoidal pulse signal generated by the signal transmitter (4) should be less than The pulse repetition period is not less than , where c is the speed of sound in water.

6. A measurement method using the high-frequency target strength measuring device for a single transducer underwater component as described in any one of claims 1-5, characterized in that, Includes the following steps: S1. A sinusoidal pulse signal is generated by the signal transmitter (4). After the rising edge of the synchronization signal level of the signal transmitter (4) is detected by the T / R switch (3), the T / R switch (3) is switched to the transmission state to control the transducer (1) to generate a pulse sound signal in the water. S2. When the synchronization signal level is a falling edge, the T / R switch (3) switches to the receiving state, controls the transducer (1) to receive the echo from the underwater component (2), and the signal receiver (5) converts the electrical signals at both ends of the transducer (1) into digital signals. S3. Adjust the position of the transducer (1) according to the size of the echo amplitude so that its main beam is aligned with the underwater component (2), and at the same time, the signal receiver (5) extracts the mirror reflection wave and elastic scattering sound wave in the echo signal. S4. Calculate the target strength of the underwater component as follows: in, Let ω be the angular frequency of the sound wave, and r be the distance between the transducer (1) and the underwater component (2). To reflect sound waves as a mirror, It is an elastically scattered sound wave.

7. The calibration method for a hydrophone calibration system based on acoustic contrast measurement according to claim 6, characterized in that: The signal extraction method of the signal receiver (5) has the following steps: 1) Perform peak detection on the received signal and extract all peak points of the received signal. The i-th peak point is denoted as . , where t i Let i be the time of the i-th peak. Let be the signal amplitude at time i. 2) Subtract the times of two adjacent peak points to obtain... ； 3) Obtain The maximum value, for all Compare with a threshold; if it exceeds the threshold, then a judgment is made. The effective peak value is denoted as . ; 4) To If sorted, then... , N is the index of the last peak. The time of any two adjacent valid peaks is subtracted to obtain... and obtain maximum value Looking for the first one Then there is , . 5) In to The signal within a time period is a specular reflection wave, in to The signal within the time interval is an elastically scattered wave.

Images